Engine lathe



w. M. M CONNELL ENGINE?- LATHE Filed June a, 1942 7 Sheets-Sheet? INVENTOI Q 7 7. WW 1. mm

7 Sheet S-Sheet 3 E-NGINE LATHE W. M. M CONNELL' Filed June 8, 1942 Jan. 30, 1945.

Jan. 30, 1945. w, MCCQNNELL ENGINE LATHE 1 Filed June 8 1942 TSheets-Sheet 5' I INVEN'ITOR W m 7m chm/e11 Jan. 3@, 1945. w MCCQNNELL 2,368,150

ENGINE LATHE Filed June 8, 1942 '7 Sheets-Sheet '7 FIG. XI7JI i 9 i -65(Z 59 64 1 I 5 6512 62 6 mzmmzfarw Patented Jan. 30, 1945 ENGINE LATHE William M. McConnell, McKeesport, Pa., assignor to Mackintosh-Hemphill Company, Pittsburgh, Pa., a corporation of Delaware Application June 8, 1942, Serial No. 446,265

13 Claims.

This invention relates to an engine lathe and particularly to a tool-feeding organization of the engine lathe adapted to the performance of various cutting operations on stock, which feeding organization is capable of relationships between its elements novel in engine lathes and useful in practice.

Generally to describe my engine lathe with reference to general knowledge in that art, the lathe comprises the general organization usual in instrumentalities of that type which is capable of performing all turning operations; having a base and head stock containing speed reducing gearing, a face, or work, plate rotatably mounted and operable by way of the power connections contained in the head stock, a tool carriage composite of a base plate mounted for movement longitudinally of the lathe bed, and a cross-slide mounted in the base plate of the tool carriage for movement therein transversely of the lathe bed, and an organization of power-transmitting connections arranged to cause both movement of t e Carriage longitudinally of the lathe bed and to cause transverse movement of the cross-slide in the base plate of the carriage.

In accordance with my invention an engine lathe adapted to the above-noted unspecialized sort of work is provided with uch organization of its tool-feeding means and connections that in making a taper cut the angle of the taper is unaffected by the changes in the speed of cutting, and one in which the angle of the taper and the speed of the cut may be regulated independently of the speed at which the work is rotated, as well as independently of each other. organization I include primary power-delivery means in the form of a feed shaft extended longitudinally of the lathe bed and which is driven from the head-stock of the lathe; and secondary power-delivery means in the form of at least one lead, or power, crew which is driven by connection with the feed shaft and which is arranged parallel to the feed shaft to give a cooperative return line of power-delivery. As will appear,

the feed shaft forming the primary power-delivery means of the lathe is organized to produce movement of the cutting tool either by functioning indirectly as a drive shaft, by functioning directly as a drive shaft, or by functioning itself as a lead screw.

In accordance with my invention an engine lathe of the type specified is provided with an arrangement of tool-feeding means and cotnnections so organized that power for moving the cutting tool longitudinally of the lathe bed is obtainable from the secondary power-delivery means to make a straight out along the work, cross movement of the tool toward and into the-work is obtainable from the primary power-delivery means, and connection to both the primary In this iii) (CI. 82-21) I power-delivery means and secondary power-delivery means may be made simultaneously to cause both longitudinalqand transverse movement of the cutting tool along and into the work, in making a taper cut.

In accordance with my invention an engine lathe of the type specified is also provided with tool-feeding means andconnections so'organized that the tool-carryihg assembly may be connected for movement longitudinally of the lathe bed and of the work, solely with the primary power-delivery means, and independently of the secondary power-delivery means, for cutting threads in the Work.

In accordance with my invention, I provide in an engine lathe having one or more longitudinal power-screws, forming the secondary powertransmiting means of the lathe, and a carriage or carriages, mean for engaging a carriage se- 1 lectively either with one of the said longitudinal power-screws or with a screw-threaded portion of the feed shaft forming the primary power-delivery means of the lathe for longitudinal movement of the carriage; associated protective means for preventing each such carriage from being engaged simultaneously with both the said primary and secondary power-delivery means.

In accordance with my invention an engine lathe of the specified type is provided with primany and secondary power-delivery means so organized with respect to each other that they may be used selectively and cooperatively to deliver power to instrumentalities of different sort for performing various metal working operations.

In accordance with my invention I provide in an engine lathe a novel structural organization in the face plate of the lathe, and in its immediate driving means.

In accordance with my invention I also include in the organization for driving the primary power-delivery means, or feed shaft, of the lathe a, gear assembly in which the gears may be shifted to giveregulation in the speed of the feed shaft, Within limits, without resorting to the bodily. removal and replacement of a set of change gears, and in which means for preventing accidental cross connection between gears is provided.

As general objects of my invention I may give the provision of an engine lathe capable of unusually great power, with consequent relatively great depth and Width in its cutting and consequent rapidity in completing the operations which it performs; the provision of an engine lathe capable of performing with nicetya wide range of cutting operations; the provision of an engine lathe capable of facilitated regulation in determining the degree of taper in making a taper cut, and in determining the speed of tool movement; the provision of an engine lathe which is capable of wide range in the magnitude of its cutting operations; the provision of an engine lathe which operates smoothly in heavy duty; the provision of an engine lathe in which the work is so directed amongst the power-delivery screws of the tool-feeding connections that at least one lead screw capable of producing 1ongitudinal movement of the cutting tool is used only in operations of particular sort, and is thus preserved in condition for particularly accurate performance; and the provision of an engine lathe capable of performing varied operation in which the work of the lathe operator is simplilied and misuse of the lathe is guarded against.

In the accompanying drawings illustrative of one physical embodiment of my invention,

Fig. I is a schematic plan view of the powerdelivery connections of an engine lathe organized in accordance with my invention.

Fig. IIa is a schematic elevation of an organization of reversing gears taken in the plane of the section line IIII of Fig. I in the line of powerdelivery to the feed shaft, or primary power-delivery means, of the lathe, showing the gears in position to actuate the feed shaft in one direction of rotation.

Fig. II?) is a similar view showing the gears in position oppositely to rotate the feed shaft of the lathe.

Fig. 1110. is a diagrammatic representation of a gear train arranged for the rapid traverse of the tool carriage longitudinally of the lathe, independently of the main actuating connections of the lathe.

Fig. III!) is a schematic plan view of the train of gearing shown diagrammatically in Fig. 11141.

Fig. IVa is a view partly in schematic elevation and partly diagrammatic taken at the tail end of the lathe, showing gears for transmitting power from the feed shaft of the lathe to a pair of power-screws extended toward the head of the lathe and from which power for actuating toolcarrying instrumentalities, such as the carriage of a tool-carrying assembly may be taken by way of power-screws, or secondary power-delivery means, this figure of the drawings showing a meshing of the gears to drive the two powerscrews in opposite directions.

Fig. IVb is a view similar to Fig. IVa, but showing the gears meshed for rotation of the powerscrews in the same direction.

Fig. Va is a side elevational view of approximately one-half of my engine lathe showing the general organization of its parts, the portion of the lathe shown being the head portion including the head stock and face plate of the lathe, and showing one tool-carrying assembly movably mounted on the bed structure of the lathe.

Fig. Vb is a similar view showing the other approximate half of the lathe and showing the tail stock of the lathe, a second tool-carrying assembly movably mounted on the lath-e bed, and a rapid-traverse organization for both tool-carrying assemblies.

Fig. VI is a cross-sectional view taken through the lathe structure in the plane of the section line VI-VI of Fig. Va showing partly in cross-section and partly in elevation a tool-carrying assembly, and means for operatively connecting the tool-carrying assembly for longitudinal movement to one of the longitudinal power-screws forming the secondary power-delivery means of the lathe.

Fig. VII is a fragmentary detail view of the means for engaging a carriage to one of the power-screws of the lathe, the view being taken in cross-section in the plane of the section line VII-VII of Fig. VI.

Fig. VIII is a front elevational view on an enlarged scale in the general region of the lathe shown in Fig. VI, showing the arrangement and mounting of means for the selective engagement of the tool-carrying assembly either with one of the longitudinal power-screws forming the secondary power-delivery means of the lathe or with a screw thread on the feed shaft, and for preventing simultaneous connection of the tool-car rying assembly with both the said screws.

Fig. IX is a fragmentary detail view showing partly in side elevation and partly in vertical section control and adjusting means shown in Fig. VIII.

Fig. X is a cross-sectional view through the organization of means for connecting the tool-carrying assembly with one of the secondary powerdelivery elements of the lathe, taken in the plane of the section line XX of Fig. Va.

Fig. XI is a cross-sectional view taken in the plane of the section line YJ XI of Fig. Vb, showing only the means for connecting the toolcarrying assembly with the thread of the feed shaft.

Fig. XII is a vertical-sectional view through the structure shown in Fig. XI, taken in the plane of the section line XIIXII of Fig. XI.

Fig. XIII is a schematic view of the set of apron gears through which a cross-feed screw, for producing transverse movement of the cross-slide of each of the carriages, receives power from the feed shaft of the lathe.

Fig. XIV is a schematic view showing a gear train which may operatively be meshed, by means of a change gear with a gear in the train of apron gears, alternatively to actuation of the cross-feed screw to actuate a secondary crossscrew which may be used to produce transverse movement of a tool rest mounted on the crossslide of a lathe carriage.

Fig. XV is a similar view of the same gear train, but viewing the gear train from a position at right angles to that from which it is viewed in Fix. XIV.

Fig. XVI is a central vertical-sectional view through the face plate of the lathe, showing the spindle of the face plate and driving connections for the face plate.

Fig. XVII is a plan view of the feed box through which the feed shaft of the lathe receives power, the cover of the feed box being broken away to show the speed-change gears and interlock for such gears inside the feed box.

Fig. XVIII is a longitudinal vertical section, taken in the plane of the section line XVIII XVIII of Fig. XVII, showing the shifting and interlock assembly of Fig. XVII.

Fig. XIX is a schematic plan view of the interlock structure, showing the said structure in full lines in it vertical position, and in dotted lines showing the said interlock in one of its two alternative functional positions.

Referring to the accompanying drawings, which show a physical structure exemplifying my invention, I first direct attention particularly to Fig. I and associated figures of the drawings showing diagrammatically or schematically the powertransmitting elements constitutin the structure 4 from which my novel and advantageous effects arise. In the drawings reference numeral I designates the head stock of the lathe, and reference numeral 2 designates the gear from which power is transmitted directly to the face plate 3 and the spindle 4 which it carries. Operating power for the lathe is supplied by an electrical motor 5 through a train of speed-reducing gears, which train is designated generally by reference numeral 6, both to a pinion 'l meshing with the driving gear 2 for the face plate, and through change gears 8 and feed box 9, containing a speed-reducing or speed-increasing gear-shift assembly, with a connector shaft H]. Connector shaft 16 through a tumbler box H, containing an assembly of reversing tumblers, to be described more in detail hereinafter, actuates a feed shaft A which is extended longitudinally of the lathe bed. At the rear or tail of the lathe, feed shaft A carries a slidable gear l2 which meshes with a gear [3, mounted on shaft i l and arranged through a reversing tumbler organization designated gen-.

erally by reference numeral l5 to drive power-screws B and C. The power-screws B and C are engageable by split nuts (indicated respectively at b and 0,) with two lathe carriages D and E shown in Figs. Va and -Vb+ for moving them longitudinally of the lathe bed R. A motor I 6 operatesa rapid traverse ear train designated generally by reference numeral I! by which the power-screws B and C may be actuated, for movement of the lathe carriages longitudinally of the lathe more rapidly than is provided in normal lathe operation.

Apron gear assemblies, designated generally 18 and 19, associated with feed shaft A are organized to transmit power for moving cross-slides F and G respectively in carriages D and E transversely across the lathe bed and at right angles to the feed shaft. The feed shaft A is both splined and threaded, the splined member 38,

through gears iBa etc. being operatively connected for producing cross movement of the cross slides F and G, and the threading on shaft A permitting it to operate as a lead screw so that it may be used alternatively to the power screws B and C to cause longitudinal movement of the lathe carriages D and E. Thus it will be seen that the single source of power, namely the feed shaft A, functions to move the lathe carriages longitudinally and through the medium of the spline and shiftable clutch 38 may cause transverse movement of the cross slides.

Considering briefly the general functions of the lathe in making taper cuts, without reference to the structural details of its physical embodiment, it will be seen that a taper cut is made by connecting one of the carriages D and E to one of the power-screws which causes longitudinal movement of the carriage with respect to work positioned by spindle l of face plate 3 and the spindle 29 of a tail stock H, or which is otherwise slidably supported in the lathe. Connection between the cross-slide of a carriage and the feed shaft A being made through one of the gear assemblies l8 and !9, the speed of movement transversely of the lathe bed is determined by-the speed of the feed shaft and the organization of the gearing which connects it with the cross-slide. The speed of longitudinal movement of the carriage. in which the cross-slide is transversely movable, is determined primarily by the ratio between gears l2 and it which are change gears, as well as by the speed of the feed shaft. By selecting an appropriate set of change gears for the gear assembly which connects the cross-slide of the carriage to the feed shaft for movement of the cross-slide across the lathe bed, the speed of that movement is determined. Power for both the longitudinal movement and the cross movement is derived initially from the feed shaft A. There is thus a definite ratio established between longitudinal feed of a tool carried by the cross-slide and transverse movement of the tool, so that for any sequence of work the angle of taper is determined. This angle is wholly independent of the speed at which the feed shaft is rotated because, as is apparent, the ratio once set will remain constant for the longitudinal feed of the carriage and the transverse feed of the cross-slide regardless of the rate at which the feed shaft rotates and the cut is made.

It has been noted that gear l2 and gear I3, which transmit power from the feed shaft to the power-screws, are change gears. The usual or standard ratio of such gear and pinion is 1 to 4, (as shown) which ratio is suitable for straight cutting, and for many taper cutting operations. If in taper cutting, however, it is desired to increase the speed of longitudinal tool travel with respect to the speed of cross movement to a ratio which cannot suitably be established in change gear assemblies l8 and 19, gear l2 and gear 53 may have a different ratio, such as a 3 to 4 ratio, thus adjusting the fundamental ratio between feed shaft speed and power-screw speed. The final ratio between longitudinal feed and crossfeed is then made by selection of change gears I8 and IS on the basis of that fundamental ratio. The speed of rotation of face plate 3 and the speed of rotation of feed shaft A may also be varied relatively to each other without disturbing the ratio between longitudinal feed and cross feed which determines the taper. Thus, by regulating the speed of feed shaft A effected either in feed box 9 or by substitution in the set 8 of change gears between connector shaft it and face plate 3, the rotation of the face plate and the movement of the tool may be given different relative speed ratios, merely by regulating the speed either of the face plate or of the feed shaft. In so doing it is unnecessary to readjust the set ratio between longitudinal feed and cross feed of the cutting tool. Since the ratio between longitudinal feed and cross feed is independent of the feed shaft speed, change in the speed ratio between the feed shaft and the face plate will not disturb that ratio, no matter how that adjustment is made.

To make a straight out, that is a cut of uniform depth along the work, one of the carriages is connectedto a power-screw and the tool entered to th desired depth of cut. The speed of the power-screw and the longitudinal speed of the carriage which is connected to it will in such case be regulated relatively to the speed of the face plate and the selected width of cutting tool to give the desired overlap to perform a smooth uniform turning of the work.

In the event that the lathe is used for thread cutting, the selected carriage is connected with the threading of the feed shaft A by one of the nuts indicated a and a in Fig. I, and the longitudinal movement is entirely free from the influence of the power-screws B and C. The desired ratio between the speed of the face plate and the speed of the feed shaft gives the proper tool feed for cutting a thread when such connection is made. It may here be noted that, because it is not subjected to service in taper cutting and straight cutting, feed shaft A is permitted to retain its threads in unbattered condition. Approximate mathematical precision in thread cutting is therefore possible. It is also possible to interjeot a thread cutting operation into a sequence of identical tapering operations without requiring that the lathe be reset after the thread cutting. Adjustment in the speed ratio of feed shaft A and face plate 3 is made in the conventional manner, by shifting gears in feed box 9 up to the limit of the range which is provided in it, and establishing ratios beyond that range by means of change gears 8.

The lathe is capable of all the conventional functions found in engine lathes. Taper cutting, straight turning, and screw-threading have been described. Facing, or cross cutting, may be done in conventional manner either by power feed, or by hand feed. In the former the cross-slide is connected to the feed shaft, through the apron gears without any connection for longitudinal movement. In the latter the tool may be fed by actuation of the cross-feed screw by applying a wrench to the squared end 21 of that screw.

Also a boring operation may be performed on the work in conventional manner, by directing the tool toward the face plate and making connection of the carriage to one power-screw, for longitudinal movement toward the face plate. If, however, my lathe comprises two carriages (as shown) and a long piece of work is to be bored, one carriage may carry the boring tool and the other carriage working between it and the face plate, may perform a taper cutting, straight turning, screw-threading or facing operation also on the stock. Whereas the other noted operations may be performed simultaneously with a boring operation in prior forms of engine lathe, the ability to perform taper-cutting at the same time as a boring operation is a feature rising from the novel organization of my lathe in which the ratio for taping is independent of speed.

The connections shown in Figs. Ila, llb, Illa, IIIb, IVa and IV 22 are of conventional structure, and in part have a conventional association in the organization of the lathe. They will, however, be here described as elements of the complete organization of the lathe. The tumbler mechanism contained in tumbler box H which is schematically shown in Figs. Ila and Ilb of the drawings comprises a triangular bracket 23 swingingly mounted about connector shaft in as a center, and carrying tumbler pinions 23a and 2312. In Fig. Ila tumbler pinion 23a is shown in mesh with gear 24 on connector shaft IE! and also meshing directly with gear 25 on feed shaft A. If then connector shaft Ill be rotated clockwise, the feed shaft A will also be rotated in a clockwise direction. By shifting bracket 23 and without changing the direction of rotation of connector shaft l9, pinion 23?) which meshes with pinion 23a is brought into mesh with gear 25 on the feed shaft. Movement is thus transmitted from gear 24 through pinion 23a to pinion 23b and thence to gear 25 on the feed shaft so that rotation of the feed shaft is counter-clockwise. Reversal of the feed shaft reverses all normal set operations of the lathe.

The rapid-traverse gear train is shown in Figs. Illa and lIIb and also in Fig. I, the position of the gearing with respect to the elements which it connects being rationalized in these figures of the drawings to permit all the gear elements to be clearly shown. In this gear train a pinion 26 is carried by the shaft of motor l6, and meshes with a gear 27 which carries a pinion 28 meshing with a gear 29. Gear 29 in turn meshes with gears 30b and 30c on the power-screws B and C respectively. By operation of this rapid-traverse either or both carriages of the lathe may be brought rapidly to working position by rotation of the power-screws B and C independently of the feed shaft A. The gear train shown act as a speed-reducing train between the motor l6 and the power-screws. In the actual construction the arrangement is vertical, beginning with the motor l6 and the pinion 25 carried by the motor shaft as the uppermost elements of the organization. Desirably gears 30b and 30c are carried by fast and loose sleeves normally idling on powerscrews B and C, but either or both of which is operatively engageable with the power-screw on which it idles by means of a sliding jaw clutch.

The tumbler organization shown in Figs. Wu and IVb, as above indicated, transmits power from feed shaft A .to power-screws B and C, either to rotate the power-screws in the same angular direction or to rotate them oppositely to each other. As shown in Figs. IVa and IVb, feed shaft gear 12 meshes with gear l3. On shaft I4 of this gear there is mounted a pinion 32. Power-screws B and C carry respectively pinions 33b and 330, and a tumbler 3'! centering about the powerscrew B carries pinions 34 and 35. Fig. IVa shows pinion 32 in mesh with pinion 330 on power-screw C, and pinion 35 of the tumbler in mesh with pinion 32 and with pinion 33b on powerscrew B. The direction of rotation of powerscrews 13 and C is thus opposite. In Fig. IVb the tumbler is in such position that pinion 35 is out of mesh with pinion 32 and pinion 34 is in mesh both with pinion 330 which directly drive power-screw C from pinion 32 and in mesh with pinion 3312 on power-screw B. In this adjustment power-screws B and C are, therefore, rotated in the same direction. This tumbler organization gives also an accommodation to rotation of one of the power-screws without rotation of the other by the quick traverse of the assembly. If then the power-screws are disconnected from the feed shaft by sliding gear l2 out of mesh with gear [3, and the tumbler 31 is swung into neutral position in which neither the pinion 34 nor the pinion 35 is in mesh either with pinion 32 or with pinion 330; that is, in a position intermediate those in which it is shown in Figs. IVa and IVb, power-screws B and C are operatively disconnected from each other so that they may be actuated-individually and selectively by the rapid-traverse.

It may be explained that the tumbler organization permits carriages D and E to b moved longitudinally of the lathe bed either toward each other, away from each other, or in the same direction. The meshing being that shown in Fig. IVa, movement of the carriages toward or away from each other by opposite rotation of the power-screws is established by the direction of rotation of feed shaft A, determined by the tumbler mechanism shown in Figs. Ila and Ill). When the carriages are moved in the same direction this tumbler mechanism of Figs. Ila and Ilb also determines whether that direction be toward or away from the head stock.

Figs. I and XIII show mean associated with each of the carriages D and E for moving their respective cross-slides F and G across the lathe bed at right angles to the feed shaft. A description of one of these organizations, such as the assembly l8, will serve for both because they may be, and desirably are, identical. Taking the organization 18 as exemplary, bevel gears l Ba and lb are either fast or loose on feed shaft A under the control of two-way clutch 38 splined on the feed shaft and shiftable by lever 22. Both bevel gears Ma and l8b mesh with a bevel gear we on the stem of which is a pinion 18d meshing with a gear l'8e, which drives a train of change gears designated 18h, 18 Nil,- IBm and which.

movement longitudinally of the lathe bed has been above discussed, and it has been noted that my organization comprises means for preventing connection of each of the carriages simultaneously, both to a power-screw and to the threading of the feed shaft operating as a lead screw. The

means making such connections positively selective wvill now be described.

Considering the organization described above by which the cross-slide of each carriage is connected with the feed shaft for movement across the lathe bed, the bevel gears 18a and it?) are sleeve-mounted, so that they may move longitudinally of the feed shaft A in longitudinal movement of the carriage. The clutch 3B, which is splined to the feed shaft, is also movable longitudinally thereof. The action of the feed, shaft A differs wholly in its different functions, functioning as a lead screw in producing longitudinal carriage movement and functioning as a rotary driving element in producing transverse movement of the cross-slide. It is therefore possible to take power for both movements directly from the feed shaft, by engaging split nut 41 with the feed shaft, and by engaging appropriately one of the bevel gears i811 and l8b by means of clutch 38-.

This use of the feed shaft simultaneously to produce both longitudinal and cross movement of the cutting tool is to be considered solely as an emergency measure, which permits simple tapercutting carried on under power in the event that there should be a break-down in the organization of the power-screws. Long continued or frequent use of the feed shaft in this described mannor would obviate an advantage of primary impcrtance in my lathe. which is the reservation of the feed shaft threading for the accurate cuttin of threads. 7

Referring to Figs. VI to XII inclusive, and assumin that we are concerned specifically with carriage D to which carriage E is identical, it

will be seen that the carriage is equipped with a split nut 40 adapted to be engaged with and disengaged from power-screw C. Split nut 40 is formed of two interiorly threaded sections which may be brought together upon or separated away from the power-screw. The carriage apron is also provided with a split nut 4|, the two interiorly screw threaded sections of which may be brought together operatively to engage the threaded feed shaft A, or may be separated to release the shaft. Movement to efiect these actions initiates respectively in manually operable lever arms or handles 42 and 43.

, First to describe the means shown for engaging the carriage to the feed shaft operating as a lead screw, operating lever 43 is keyed to a shaft 44 which carries a slotted cam disk 45 into the slots 45a of which 'extend pins 46a and 46?) carried respectively by the two sections 41a and 41b of the split nut 4]. It is to be understood all that these slots are so arranged that rotation of the cam disk in one direction separates the jaws of the nut, and that rotation of the cam disk in the other direction moves them toward each other operatively to engage the feed shaft. An interlock disk 41 cooperative with another interlock disk 48 (Fig. VIII), the cooperative functions of which disks will be described, is keyed to the shaft 44. Given the problem presented by my novel organization in which a carriage may be connected for longitudinal movement either to a primary or secondary power-delivery means, various equivalent interlocks to prevent simultaneous connection to both maybe devised.

The organization for connecting the carriage to the power-screw C by a split nut for movement longitudinally of the lathe bed, shown particularly in Fig. VI, comprises an operating shaft 49 which carries a pinion 50 meshing with a quadrant gear 5| rigidly connected with a short shaft 52 turned by operating lever or handle 42, and rigidly connected withthe interlock disk '48 also carried by the shaft 52. Operating shaft 49 has two oppositely screw threaded sleeves 49a i and 491), which respectively engage cooperatively in interiorly threaded nut portions 40a and 48b of the two sections 40a and 40b of the split nut. Rotation of operating shaft 49 in one direction thus serves to bring the sections 400. and 40b of nut 40 toward each other into operative engagement with power-screw C, and rotation of the operating shaft in the opposite direction moves the nut sections 40a and 40b apart,'releasing the nut.

Referring particularly to Fig. VIII of the drawings, it will be seen that interlock disks 41 and 48 are mounted in interfering position, but that a peripheral portion of each is removed, the line formed by the edge of the disk at each of these removed portions being on an are formed on the same radius as the equal radii of the two disks, and this inverse arc of each disk being concentric with the center of rotation of the other disk. Each of the disks can then be rotated only when the disks are in such position that its periphery fits into and can slide along the arcuate indentation of the other disk. Thus in Fig. VIII the elements of the interlock are in a relation appropriate to the showing of Fig. VI in which the split nut 40 is engaged with power-screw C. It will be seen in Fig. VIII that in this position the disk 48 associated with operating lever 42 which actuates operating shaft 49 lies partially within the arcuate indentation 41a of the disk 41, and that the disk 41 cannot be moved.

By swinging operating lever 42 into dotted line position interlock disk 48 is brought into a position in which its indentation 48a matches the indentation 41a of disk 41, the arcs upon which both indentations are formed being bi-sected by a line passing through the centers of rotation of the two disks. That movement, by moving quadrant rack 5| meshing with pinion 50 on operatin shaft 49 has also served to disconnect split nut '40 from the power-screw C. In this condition operating lever 43 can be swung to the left in Fig. VIII to rotate shaft 44 carrying cam disk 4.5, and thus engage split nut 4| with feed shaft A. When this has been done a portion of interlock disk 41 will lie within the arcuate notch 48a of disk 48, and will thus prevent movement of operating lever 42 and the elements connected with it until handle 43 has been swung fully to the right to bring the arcuate indentations of the two disks again into diametric alignment.

Some interlock providing assurance against accidental cross-connection of the carriages is a feature of primary importance in a lathe made to include my novel organization, in which one or more carriages may be connected for movement longitudinally of the lathe bed selectively either to a primary power-transmitting element (i. e. the feed shaft) or to a secondary powertransmitting element (i. e. the power-screw).

The cross-feed organization has been above described, and normally that organization is used for taper cutting as well as for other tool movements which involve cross-feeding. It is, however, possible to move the compound tool rest across the lathe bed by power connection to the feed shaft of the lathe. In taper cutting in such manner, longitudinal movement of the carriage may be taken from the power-screw, and the ratio between longitudinal feed and cross-feed of the tool may be established in the connections which are provided to transmit power from the feed shaft to the compound tool rest, for giving the said tool rest transverse movement in the cross-slide. The compound tool rest I is, as shown, rotatable on its base; and it may therefore be swung to present the tool at any desired cutting angle.

The base of the compound tool rest may have a transverse slidabl mounting in the cross-slide, and an engagement of its feed screw 59 therein, which are too conventional to require illustration. A portion of this modified structure is, however, shown herein. Such modified structure is the operating connections by which power for moving the tool rest transversely in the crossslide may be taken from the apron gears. These connections are shown in Figs. XIV and XV of the drawings.

The power-transmitting assembly shown in those figures comprises a gear 53, usable as a change gear interchangeably to mesh with apron gear l8g. instead of gear l8h carried by the cross-feed shaft 39. broken lines in Fig. XV of the drawings, the compound feed gear 53 being shown in full lines therein. Gear 53 is carried by a spline shaft 53a on which bevel pinion 54 is slidably mounted. Bevel pinion 54 meshes with bevel pinion 55 on a shaft 56 carrying a second bevel pinion 51 which in turn meshes with a bevel pinion 58 carrying a nut 58a engaged with compound feed shaft 59.

It will be seen that by this arrangement of actuating connections, transverse movement of the tool rest may be obtained merely by interchanging gear 53 for gear |8h in making connection to the train of apron gears.

Amongst the other structural elements of my lathe are several which present novel features of particular utility. Thus, although the screw and micrometer assembly J, usually termed in the art a thread chaser dial, the rack K and its associated pinion L, operable by hand or from the power feed to produce longitudinal movement of the carriages along the lathe bed; the rack M arranged to produce longitudinal movement of the tail-stock H, and other of the apparatus elements are conventional in engine lathes, several other of the operating and control elements of the lathe are novel.

Among these novel elements are the feed box 9, in which a selection of gear ratios may be obtained for regulating the speed of the feed shaft The gear [8h is shown in handles.

A. In this organization I associate a safety lock of novel sort positively to prevent cross-meshing of the gears.

In the transmission assembly shown in Figs. XVII, XVIII and XIX, gear 60 and double gear 6! which includes gear elements Bla and Slb, are shiftable. Gear 60 may be meshed either with gear 62 or with gear element 631) of a double gear 63 including gear elements 63a and. 632). Gear element 61b of the shiftable double gear may be meshed with gear 54 or gear element Gla of the double gear may be meshed with gear 65. It naturally follows that gear and two-element gear 6! should not simultaneously be meshed. In order that such result positively is prevented an interlocking structure is associated with the means for shifting the gears.

The gear-shifting elements include two forks 68 and 61 which embrace respectively the gear and the element (lid of double gear 5|. These forks are carried respectievly by operating handles '58 and 69 having stems 68a and 69a threaded in the forks. The upper portions of the handles are resiliently urged against the cover 10 of the feed box 9, and overlap marginally the slots H therein in which the stems 68a and 69a of the shifting handles lie. At the ends of the slots H are sockets Ha in which the shifting handles rest at the limit of the shifting movement of each in either direction.

The safety feature of the gear shifting assembly consists of a locking bar 13 pivotally mounted by a pintle 72 against the under surface of the feed box cover 10 to lie adjacent the slots H in the feed box cover. The locking bar, or plate 13 has a central portion 13a in which it is pivoted, and arms 14 and '15 extended in opposite directions from its central portion. The edges Ma. and a of these arms which are presented toward the slots have in them notches or indentations 74b and 15b, which lie opposite the stems 68a and 69a of the shiftinghandles in the neutral position of the handles, close to but not quite touching the stems.

Referring to Fig. XIX of the drawings, the full line position of the locking bar is its neutral position, corresponding to the neutral position of the forks 66 and B1. and the gears which they move, shown in Figs. XVII and XVIII of the drawings. In this showing, it will he noted that if the lines indicating the edges of the arms 14 and 15 were made continuous to eliminate notches 14b and 15b, these lines would pass through the stems 68a and 69a of the shifting This being so, movement of either of the operating handles in either direction is accompanied by swinging movement of the locking bar. The dotted line portion of the locking bar shows the gear 60 shifted to the left to mesh with gear 63b of the double gear 63. In its movement it has pressed against tapered urface 14a of arm M and has swung the arms 14 of the locking bar away from the slots H. In this action the arm 15 has been swung toward the slots, so that the stem 69a of handle 69 is engaged by the notch 15b. In this engagement, handle 69 cannot be moved to shift double gear 6! until handle 68 is again moved toward neutral position. When handle 68 is moved into neutral position, the locking bar is released from the obstruction to swinging movement presented by its stem 68a, and may swing in accordance with movement of handle 69. Substantially the same condition exists when operating handle 68 is moved to the right (toward pintle 12), to mesh gear 60 with gear element 62. In this position also stem 68a of the shifting handle presents such obstruction to opposite swinging of the looking bar that handle 69 cannot effectively be moved until stem 58a is again aligned with notch 14b. Movement of handle 69 from from its neutral position acts similarly to prevent effective movement of handle 68 until swinging clearance is again provided by realignment of stem 69a with notch 1517.

This interlock permits the use of a transmission which provides a wide range of different speeds, such as the feed-box transmission shown herein, while providing positively against disablement of the lathe by preventing cross-meshing of the gears by incompetent or careless. operation of the lathe, In the organization of my lathe the provision of an effective interlock, such as the interlock shown, is of primary importance. This is because it is desirable to provide as wide a speed variation as is possible by simple gear shifting, thus decreasing the frequency with which the relatively laborious operation of changing gears 8 must be performed.

Novelty is also found in the structure of the face plate forming an element of my lathe. Referring to Figs. VI and XVI of the drawings, it will be seen that face plate 3 comprises, as an integral part of its structure, a hub 89 keyed to the spindle 4 of the face plate. Keyed to and shrunk upon the hub 89 of the face plate, there is a gear 2, with which meshes the driving pinion 1. Pinion is carried by a shaft 8i driven from the head stock I. As shown, face plate 3 has therein four pairs of slots 82 spaced 90 apart about the center of the lathe. These paired. slots form tracks, or ways, providing mounting for work-engaging chucks 83 in different adjusted positions radially of the face plate. As shown, these work-en aging chucks 83 are of conventional structure. Intermediate the paired slots 83 are additional radial slots 84, which serve for the mounting of work-positioning dogs, usable when work is engaged between the center 85 carried by the spindle 4 of the face plate and another center, such as the center 86 on the spindle 20 tail stock H.

The structure of the face plate assembly is such as to conform to high power delivery by the lathe, and such as to contribute to smoothness in its delivery of such high power. Thus the hub- 80 is of one piece with the remainder of the face plate structure proper, and is secured to the spindle 4 of the face plate by key 81. Gear 2 is secured to hub 8i) both by shrinkage and by key 88. This structure, because it em ploys integrating means of the sort shown, which eliminates bolts, is free from the element of weakness caused by the tendency of bolts to fail under shear. The provision of a hub of one piece with the face plate proper, and the keying of this one-piece structure to the spindle of the face plate, also contribute to give a structure of great strength relatively to face plates previously included in engine lathes. Because of the compactness of the organization it is practical to use an external rather than internal gear to drive the face plate. This permits the use of a gear 2 and pinion 1, having respectively faces 89 and 9D furnished with herringbone teeth such as those shown. Such gears, as is well known minimize chattering, and tend to greatly increased smoothness in the delivery of power for rotating the work. By eliminating chatter, they make an increased cutting depth possible.

Referring particularly to Figs. Va and Vb, some brief mention of controls for the lathe operation may be made. The main driving motor 5 for the lathe, indicated in Fig. I of the drawings, is under the control of lever 9| on control shaft 92 which acts on drum switch 93 which serves to make and break electrical connection for energizing and deenergizing the main motor. Drum switch 93, by an organization whichis .not shown, functions to energize the motor only when the oil pressure in the head stock has been built up to a safe value.

The other general control shown in Figs. Va and Vb is also a safety control. This control is by lever 94 on operating shaft 95 for a drum switch 96, which controls the rapid-traverse motor I6. With this drum switch 96, also, there is associated a safety feature. Thus limit switch 91 must be thrown in order that energization contact in drum switch 96 may be made. Limit switch 91 is operated through levers 98 from a manually operable lever 99 which acts on slide gear 12, carried by the feed shaft A. When by operation of lever 98, slide gear 12 is moved out of mesh with gear I3 by which power is transmitted to the power-screws B and C, limit switch 91 permits energizing contact for motor 16 to be made through the drum switch, and when reverse movement of the lever brings gears l2 and I3 into mesh limit switch 91' is in such condition that current cannot pass to the drum switch.

A second limit switch, indicated at H39 acts in accordance with the connection or disconnection of tumbler 3'! (Figs. IVa and IVb), and provides a second interlock to inhibitenergization of the rapid-traverse motor l6. Reversing tumbler 37 must be in its neutral position, so that power-screws B and C are unconnected with each other through the pinions of the reversing tumbler, in order that energizing current may pass to the rapid-traverse motor.

It will be understood from the foregoing that my engine lathe presents features which are novel and useful in a lathe of a character which is adapted to perform various operations. on stock, and which thus is adapted to the adjustment of its operating elements and the regulation of the operation which it performs. It is thus distinguished from special lathes organ-.

ized to be operated in accordance with a pattern to perform successive identical series of operations.

In an engine lathe of the sort in which my invention resides, my lathe possessesadvantageous features, a primary one of which is its capacity to perform a taper cut in accordance with a definite set ratio of cross movement and longitudinal movement to give the desired. angle of taper independently of the speed which the lathe is operated. It is thus possible in my lathe to increase the rate of cutting in any order which may prove practical without resetting the lathe and while retaining the desired angle of taper, and it is possible similarly to reduce the speed of operation if conditions indicate that the cutting is too rapid. Also since in my lathe the angle of taper is determined by independent connection with the primary power-delivery means, or feed shaft, and with the secondary power-delivery means, or power-screw; the rate of cutting in making a taper cut may be accommodated to the width of the cutting tool and other considerations without affecting the angle of taper which is produced on the work by the operation, the rotational speed of the face plate and the work which it carries being regulatable without disturbing the connections which determine the angle of taper.

Another substantial advantage of my engine lathe is in the power application for producing longitudinal movement of the lathe carriage, or carriages. The feed shaft A lies well under the structure of the carriages, so that there is a greatly decreased tendency to twist the carriages in their tracks, and to produce a binding effect in driving from the feed shaft, as compared with structures in which pinions mounted in the carriage apron are used to feed a lathe carriage longitudinally of the lathe bed. The power application is even better centered when connection for feeding a carriage is made to one of the pownr-screws B and C which, as may be seen in Fig. VI of the drawings, lie almost centrally between the tracks on which the carriage moves.

It is to be understood that the primary features of my invention reside in an engine lathe organized with but a single carriage and a single power-screw for producing longitudinal movement of the carirage, as well as in an engine lathe comprising two carriages and two power-screws as shown and described herein. Also the number of carriages and power-screws may be increased to more than two without going beyond the bounds of my invention.

It is, however, true that there stems from my eneral organization particular advantages when two or more carriages and power-screws are used. These advantages have been described with relation to the lathe shown, which comprises two carriages mounted for movement longitudinally of the lathe bed. As above noted, in accommodation to the work to be done and for convenience in doing it the two carriages shown may be moved simultaneously toward either end of the lathe bed, or toward or away from'each other.

Various advantages other than those above specifically noted are derivable from the novel organization of my lathe, and structural changes within the ambit of the appended claims other ian those above noted may be made without passing beyond the bounds of my invention as therein defined.

I claim as my invention:

1. In an engine lathe organized for the performance of a plurality of cutting operations on stock the combination of a lathe bed, two carriages mounted for movement longitudinally thereof. a feed shaft extended longitudinally of the lathe bed. two power-screws parallelin the said feed shaft, means for operatively connecting the two said carriages each to one of the said power-screws for movement longitudinally of the lathe bed, and operating connection between the said feed shaft and the said power-screws including elements adjustable selectively to produce operation of the power-screws in the same direction of rotation and in opposite directions of rotation.

2. In an en ine lathe organized for the performance of a plurality of cutting operations on stock the combination of a lathe bed, two carriages mounted for movement longitudinally thereof, a feed shaft, two power-screws paralleling the said feed shaft, means for operatively connecting the two said carriages each to one of the said power-screws for movement longitudinally cf the lathe bed, operating connections between the said feed shaft and the said powerscrews including elements adjustable selectively to produce operation of the power-screws in the same direction of rotation and in opposite direc- 15 tions of rotation, and mechanical means organized with the said feed shaft to reverse the direction of rotation thereof and thereby to reverse the direction of rotation of the said power-screws and the longitudinal movement of the said carriages resulting from their connection thereto.

3. In an engine lathe organized for the performance of a plurality of cutting operations on stock the combination of a lathe bed, two carriages mounted for movement longitudinally thereof, a feed shaft, two power-screws paralleling the said feed shaft, means for operatively connecting the two said carriages each to one of he said power-screws for movement longitudinally of the lathe bed, operating connections between the said feed shaft and the said powerscrews including elements adjustable selectively to produce operation of the power-screws in the same direction of rotation and in opposite directions of rotation, mechanical means organized with the said feed shaft to reverse the direction of rotation thereof and thereby to reverse the direction of rotation of the said power-screws and the longitudinal movement of the said carriages resulting from their connection thereto, crossslides mounted in said carriages for movement across the lathe bed, and independently reversible operating connections between the said crossslides and the said feed shaft.

4. In an engine lathe capable of taper-cutting having a bed, a rotated feed shaft extended longitudinally of the lathe bed, a power-screw paralleling the said feed shaft and having actuating connections thereto, a carriage mounted for movement longitudinally of the lathe bed and having actuating connection with the said power-screw, across-slide mounted in said carriage for movement across the lathe bed and having actuating connection to the said feed shaft, mechanical means for reversing the direction of rotation of the said feed shaft, independent mechanical means for reversing the direction of rotation of the power-screw, and independent mechanical means for reversing the direction of movement of the cross-slide.

5. In an engine lathe the combination of a lathe bed, a carriage mounted for movement longitudinally of the lathe bed, a feed shaft extended longitudinally of the lathe bed, a power-screw paralling the said feed shaft and having actuating connection with the said carriage, a cross-slide movable across the lathe bed in the said carriage, a compound tool rest movable across the lathe bed in the said cross-slide, and actuating connections between the said compound tool rest and the said feed shaft giving movement of the said tool rest across the lathe bed in a speed ratio with longitudinal speed of the carriage which is independent of variations in the speed of the feed shaft.

6. In an engine lathe the combination of a lathe bed, a carriage mounted for movement longitudinally of the lathe bed, a feed shaft extended longitudinally of the lathe bed, a power-screw paralleling the said feed shaft and having actuating connection with the said carriage, a compound tool rest movable across the lathe bed in the said cross-slide, and actuating connections from the feed shaft to the cross-slide and to the compound tool rest including change gears effective to connect the cross-slide and the compound tool rest alternatively with the feed shaft for propulsion of either across the lathe bed in a ratio of cross feed to longitudinal feed which is independent of variations in the speed of the feed shaft.

7. In an engine lathe capable of taper-cutting,

the combination of a lathe bed, a plurality of carriages mounted for movement longitudinally of the lathe bed, cross-slides mounted in the said carriages for movement across the lathe bed, a plurality of power-screws, operating connections between the said feed shaft and the said powerscrews to rotate each of the power-screws inset speed ratio with the rotation of the feed shaft, power feed connections from each of the said cross-slides to the said feed shaft for power-feeding the same across the lathe bed at a set speed with respect to the rotation of the feed shaft, nuts on the several said carriages arranged each for threaded engagement with one of the powerscrews, to power-feed its carriage in direct accordance with rotation of the engaged powerscrew and thereby to give a speed ratio between longitudinal power feed of each carriage and transverse power feed of its associated cross-slide unaffected by change in the speed of rotation of the said feed shaft and power-screws.

8. In an engine lathe the combination of a lathe bed, two carriage mounted for movement longitudinally thereof, a threaded feed shaft, means for rotating the said feed shaft in either direction of rotation, two rotatable power-screw paralleling the said feed shaft, means for operatively connecting the two said carriages each to one of the said power-screws to be moved by rotation thereof longitudinally of the lathe bed, operating connection between the said feed shaft and the said power-screws including elements adjustable selectively to produce operation of the power-screws in the same direction of rotation or in opposite directions of rotation, and connectin means arranged to engage each carriage to said threaded feed shaft alternatively to connection thereof to a power-screw for movement longitudinally of the lathe bed.

9. An engine lathe having a bed, two parallel lines of power delivery one comprising a single rotated threaded shaft and the other comprising two rotated threaded shafts, two lathe carriages each directly engageable alternatively in either of the two lines of power delivery to be moved by rotation of a threaded shaft thereof longitudinally of the lathe bed, and mean associated with the elements of the said double power delivery line organized to cause the elements thereof selectively to propel the said carriages in the same direction or in opposite directions longitudinally of the lathe bed.

10. In an engine lathe capable of taper-cutting, the combination of a lathe bed, a carriage mounted for movement longitudinally of the lathe bed, a cross-slide mounted in the said carriage for movement transversely thereof, a feed shaft extended longitudinally beside the lathe bed, a power-screw paralleling the said feed shaft within the width of the lathe bed, operating connections to the two said shafts to rotate the same inpa set speed ratio each to each, power feed connections from the said feed shaft to the said cross-slide for powerfeeding the same across the lathe bed at a set speed with respect to the rotational speed of the feed shaft, and a nut non-rotatably mounted on the said carriage arranged for threaded engagement with the said power-screw to power-feed the carriage along the lathe bed in direct accordance with the rotation of the power-screw in a speed ratio with movement of the cross-slide across the lathe bed determined by the set ratio between the rotational speed of the feed shaft and therotational speed of the power-screw.

11. In an engine lathe organized for the performance of a plurality of cutting operations on stock, the combination of a lathe bed, a carriage mounted for movement longitudinally thereof, a tool-carrying cross-slide mounted on said carriage for movement transversely thereof, a threaded feed shaft extended longitudinally of the lathe bed, a power-screw paralleling the feed shaft, means for directly connecting the carriage operatively with the power-screw for power feed longitudinally of the lathe bed, means for simultaneously connecting the cross-slide operatively with the feed shaft for power feed across the lathe bed, and means on the feed shaft and the carriage for directly connecting the carriage to the said feed shaft for power feed longitudinally of the lathe bed alternatively to connection of the said carriage to the said power-screw, said means for connecting the carriage to the feed shaft and said means for connecting the carriage to the power screw, both being operable independently of the means to connect the cross-slide to the feed shaft.

12. In an engine lathe organized for the performance of a plurality of cutting operations on stock, the combination of a lathe bed, a carriage mounted for movement longitudinally thereof, a tool-carrying cross-slide mounted on said carriage for movement across the lathe bed, a feed shaft extended longitudinally of the lathe bed, a power-screw paralleling the feed shaft, independent means organized simultaneously to directly connectthe carriage and the cross-slide respectively to the said power-screw and to the feed shaft for simultaneous longitudinal and cross power feed movement with respect to the lathe bed, and means on the feed shaft and the carriage for directly connecting the carriage to the said feed shaft alternatively to connection thereof to the said power-screw for simple power feed longitudinally of the lathe bed unaccompanied by movement of the cross-slide transversely thereof, said means for connecting the carriage to the feed shaft and said means for connecting the carriage to the power screw, both being operable independently of the means to connect the cross-slide to the feed shaft.

13. In an engine lathe organized for the performance of a plurality of cutting operations on stock, the combination of a lathe bed, a carriage mounted for movement longitudinally thereof, a

tool-carrying cross-slide mounted on said carriage for' movement across the lathe bed, a feed shaft extended longitudinally of the lathe bed, a power-screw paralleling the feed shaft, independent means organized simultaneously to directly connect the carriage and the cross-slide respectively to the said power-screw and to the feed shaft for simultaneous longitudinal and cross power feed movement with respect to the lathe bed, means on the feed shaft and the carriage for directly connecting the carriage to the said feed shaft alternatively to connection thereof to the said power-screw for simple power feed longitudinally of the lathe bed unaccompanied by movement of the cross-slide transversely thereof, and means organized positively to prevent connection of the carriage for movement longitudinally of the lathe bed simultaneously both to the said powerscrew and to the said feed shaft, said means for connecting the carriage to the feed shaft and said means for connecting the carriage to the powerscrew, both being operable independently of the means to connect the cross-slide to the feed shaft.

WILLIAM M. McCONNELL. 

